1.Acute Inhalation Toxicity Study of 2-Fluoroacetamide in Rats
SINGH MANINDER ; R.VIJAYARAGHAVAN ; S.C.PANT ; K.SUGENDRAN ; KUMAR PRAVIN ; SINGH RAM ; PURNANAND
Biomedical and Environmental Sciences 2000;13(2):90-96
One of the most potent rodenticides is 2-fluoroacetamide (2-FA). Toxicity of this chemical is well documented. However, its inhalation toxicity data is not available in the literature. Hence, acute inhalation toxicity study was carried out by exposing male and female rats to aerosols of 2-FA at different concentrations for 4 h in a dynamically operated whole body inhalation exposure chamber. During and after the inhalation exposure the rats were less active, and showed mild tremors and convulsions. At higher concentrations the rats died after 2-3 days. The estimated 4-h LC50 for male and female rats was 136.6 and 144.5 mg·m-3 respectively. Exposure to 0.7 LC50 for 4 h duration showed an increase in the liver weight of male and female rats 7 days after exposure. Various haematological and biochemical variables determined were within the normal limits. However, histological findings showed injured lung as indicated by desquamation and necrosis of the epithelium of the respiratory tract. Marked hypertrophy of hepatocytes displaying strong acidophilic granulated cytoplasm was observed. Focal dilatation of renal proximal tubules in kidney with cytoplasmic vacuolation, and irregularly placed pyknotic nuclei were seen. The present study shows that 2-FA is a highly toxic chemical through the inhalation route based on the LC50 value. Consequently necessary precautions should be taken during its handling.
2.Subacute (90 Days) Oral Toxicity Studies of Kombucha Tea
R.VIJAYARAGHAVAN ; SINGH MANINDER ; P.V.L.RAO ; BHATTACHARYA ; KUMAR PRAVIN ; K.SUGENDRAN ; KUMAR OM ; S.C.PANT ; SINGH RAM
Biomedical and Environmental Sciences 2000;13(4):293-299
Kombucha tea (KT) is a popular health beverage and is used as an alternative therapy. KT is prepared by placing the kombucha culture in solution of tea and sugar and allowing to ferment. The inoculum is a fungus consisting of symbiotic colony of yeast and bacteria. KT is consumed in several countries and is believed to have prophylactic and therapeutic benefits in a wide variety of ailments, viz., intestinal disorders, arthritis, ageing and stimulation of immunological system. Though KT is used in several parts of the world its beneficial effects and adverse effects have not been scientifically evaluated. Since there are no animal toxicological data on KT, subacute oral toxicity study was carried out. Five groups of rats were maintained: (a) control group given tap water orally, (b) KT given 2 ml/kg orally, (c) plain tea (PT) given 2 ml/kg orally, (d) KT given in drinking water, 1% (v/v) and (e) PT given in drinking water, 1% (v/v). The rats were given this treatment daily for a period of 90 days. Weekly records of weight, feed intake, water intake and general behaviour were monitored. There was no significant difference in the growth of the animals as evidenced by the progressive body weight change. The organ to body weight ratio and histological evaluation did not show any toxic signs. The haematological and biochemical variables were within the clinical limits. The study indicates that rats fed KT for 90 days showed no toxic effects.
3.Association between anterior corneal astigmatism and posterior corneal astigmatism across age groups:a cross-sectional analysis
Shetty VIJAY ; Haldipurkar S SUHAS ; Dhamankar RITA ; Haldipurkar TANVI ; Pirdankar ONKAR ; Setia Singh MANINDER
International Eye Science 2017;17(11):1993-1999
AIM:To assess the anterior corneal astigmatism (ACA)and posterior corneal astigmatism (PCA) patterns across various age groups.We also evaluated the association between magnitudes and axes of the ACA and PCA across these age groups.METHODS:The present study was a cross-sectional analysis of clinical data of 381 eyes.We converted the clinical astigmatic notation to vector notation for analysis of ACA and PCA.We estimated the correlation between magnitude and axes of the ACA and PCA in the whole population and in four age groups (5-19,20-39,40-59,and ≥ 60y).We used random effects linear regression models for estimating the association between the magnitudes of ACA and PCA.RESULTS:The mean of the magnitude of the ACA (3.59D) and the PCA (0.50D) was highest in children (5 to 9y).Overall,the magnitude of the ACA ranged from 0D to 10.0 Diopters (D) and the magnitude of the PCA ranged from 0 to 3.5 D.There was a significant correlation between the ACA and the PCA in the younger age group (r=0.85,P<0.001).In those 60y or older,the PCA increased by 0.04 units (95% confidence intervals:0.005,0.07;P=0.03) with each unit increase in the ACA,the increase was the smallest in this age group.CONCLUSION:It will be prudent to measure the both the magnitude and axis of the PCA,particularly in those above 60y rather than rely on rule-of-thumb calculations based on ACA parameters for IOL power calculation.